Patent Literature 1 discloses a conventional spring assembly of this type. Although not shown specifically, in the spring assembly of Patent Literature 1, two spring retainers (R1, R2) are formed of a synthetic resin material. A mounting portion (2) projects from each of the spring retainers (R1, R2). After a coil spring (1) is fitted on this mounting portion (2), the mounting portion (2) is heat crimped so as to form a constriction (3) in a base portion, whereby the dislocation of the coil spring (1) is prevented.
Bracketed reference numerals represent numerals in Patent Literature 1.
In the related art configured, in order to prevent the dislocation of the coil spring (1) fitted on the mounting portion (2) on the spring retainers (R1, R2), the working step of heat crimping the mounting portion (2) is necessary. Thus, the assembling work becomes complex and troublesome, or the cycle time delays as the number of working steps increases. Further, since equipment (crimping device) which heats and collapses forcibly the mounting portion (2) is necessary, the equipment cost is increased.